It is known that devices exist which are designed to reduce the chances of sustaining a catastrophic neck injury in some, but not all, riding situations.
These devices are worn around the neck of the rider and interacts with the underside rim of the rider's helmet in order to provide an alternative load path for compressive forces. When used correctly the device can reduce the magnitude of these forces and helps avoid the type of injury that riders fear above all others: damaging their spinal cord.
An example of such a device is shown in WO2005051251 in the name of Leatt. Here the protection is just a round, quite rigid collar which may be divaricated and then arranged around the neck. It has a fixed structure once worn.
Applicant's studies have shown that a key reason why riders break their neck is that when they land upside down their head is squashed into the body and the neck is often damaged due to the compression. If one lands directly on top of his head there is a very high probability that the neck could break. However if the impact occurs to the side of the head, the chance of breaking reduces. This is because the amount of force going through your neck is reduced, i.e. less force is channeled through your neck.
Injury severity is mainly influenced by the height of the fall and not the speed over the ground. Falling on the top of your head from a height greater than 55 cm (1′ 10″) can be enough to break your neck—even if you are stopped.
Thus, the only real way to avoid breaking your neck is to limit the overall compression and one way of doing this is to offer an alternative load path around the neck. However up until now, the biggest flaw in this method of protection is that in order to allow some movement of the head (essential when riding a motorcycle) a gap must exist between the rim of the helmet and the upper surface of the device. The unfortunate fact is that this gap prevents the best load transfer and thus limits the effectiveness. The real benefit comes when there is contact (or a very small gap) between the brace and helmet at the time of impact, something that does not happen automatically.